1. Field
The following description relates to a bulk acoustic wave resonator (BAWR).
2. Description of Related Art
A bulk acoustic wave resonator (BAWR) operates by the application of an electric potential to electrodes that are disposed on and/or below a piezoelectric layer. The piezoelectric layer oscillates in response to a high frequency electric potential applied to the electrodes. As a result, the BAWR operates.
Bandwidth of the BAWR is proportional to an Acousto-electric coupling coefficient. A film characteristic of the electrodes and the piezoelectric layer affect the Acousto-electric coupling coefficient. Therefore, to increase the bandwidth of the BAWR, it is necessary to increase a value of the Acousto-electric coupling coefficient.
Accordingly, it is necessary to continuously develop technologies that improve bandwidth using the film characteristic of the electrodes and the piezoelectric layer.